Prior art artificial impedance surface antennas (AISAs) are described by D. Gregoire and J. Colburn, “Artificial impedance surface antenna design and simulation”, Proc. 2010 Antenna Applications Symposium, pp. 288, J. S. Colburn et al., “Scalar and Tensor Artificial Impedance Surface Conformal Antennas”, 2007 Antenna Applications Symposium, pp. 526-540, and B. H. Fong et al, “Scalar and Tensor Holographic Artificial Impedance Surfaces”, IEEE Trans. Antennas Propag., accepted for publication, 2010.
In the prior art, AISAs are fabricated by printing arrays of metallic patches 26 onto a dielectric substrate, as shown in FIG. 1B. The surface-wave impedance modulation is created by the printed grid of metallic patches, whose size varies according to the desired modulation. To operate properly it is critical that the size and placement of metallic patches maintain a strict dimensional tolerance. The dielectric substrate, upon which the metallic patches in the prior art are printed, is typically a high-cost, a high-frequency circuit board material such as Rogers Corporation RO3010™, which costs typically $150/sq. ft. The process of creating the array of square patches requires costly and time-consuming circuit board etching techniques.
Installation of affordable directive microwave antennas on the exterior of structures ranging from single-family homes to apartment buildings to office buildings and public structures typically involves mounting parabolic dishes or horn antennas such that they stick out from the structure and are easily visible. Many find this unsightly and would prefer a hidden antenna approach. The AISA is an affordable conformal antenna that addresses this need. However, the real estate for conformal antennas may be limited—especially in residential applications. For many applications, such as satellite reception and telecommunications, the best candidate for installation is the roof. This is far from straightforward for roof materials such as tile and even on asphalt-shingle roofs may require either drilling through the roof or running an unsightly cable down the side of the house.
Further, even though satellite dishes have been commonplace for many years, they are still thought of as unsightly. This causes some to forgo satellite television service in favor of other services such as cable television service.
What is needed is an artificial impedance surface antenna (AISA) that can be located on a roof, which is not unsightly and can be installed without harming the roof. The embodiments of the present disclosure answer these and other needs.